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Abstract: This paper presents the preparation of novel organic/inorganic flame retardants containing phosphorus, nitrogen and silicon (organic/inorganic FRs). The organic/inorganic FRs were highly water resistant, as suggested by the water contact angle and water solubility tests. The organic/inorganic FRs were then incorporated into epoxy resins (EP) at different phosphorus/nitrogen ratios and the flame retardancy of EP/FRs composites was characterized. The results showed that synergistic effects on the flame retardancy of EP composites existed between the DOPO-VTS and TGIC-KH. The char residues for EP/FRs composites were increased, and the highest char residues were obtained in air atmosphere (3.8 wt.%) when the DOPO-VTS/TGIC-KH is 4/1. The MCC results also showed that the THR of epoxy resins were also decreased when the DOPO-VTS/TGIC-KH is 4/1, which was in accordance with the highest LOI and UL-94 results. The SEM, FTIR, XPS and TG-FTIR results of pyrolysis products in both condensed and gases phases indicated that the strategy of organic/inorganic FRs combined condensed phase and gases phase flame retardant strategies such as the phosphorus–nitrogen synergism systems, the silicon reinforced effects in the condensed phase and DOPO flame retardant systems in the gases phase, resulting in significant improvements in the flame retardancy of epoxy resins. [Copyright &y& Elsevier]

Abstract: Graphene nanosheets coated with Co3O4 and NiO (denoted as GNS–Co3O4 and GNS–NiO) have been facilely synthesized and then melt-mixed with polyamide 6 (PA6) to investigate the fire retardant properties of the composites. The Co3O4 (20–40 nm) and NiO (8–15 nm) nanoparticles are homogeneously dispersed on the graphene surface, which has been demonstrated by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. Scanning electron microscopy clearly shows that graphene, GNS–Co3O4 and GNS–NiO are well dispersed in PA6 due to the electrostatic interaction. The visible increment in decomposition temperature and reduction in maximum decomposition rate are observed from thermogravimetric analysis for both PA6/GNS–Co3O4 and PA6/GNS–NiO composites. Testing in the cone calorimeter shows that incorporating GNS–Co3O4 and GNS–NiO confers PA6 with improved fire safety, as evidenced by the obvious delay in time to peak heat release and visible reduction in heat release rate, CO production rate and total smoke production. The result of the smoke density chamber indicates that GNS–Co3O4 and GNS–NiO perform better than bare graphene in inhibiting the smoke emission. The flammable gaseous products are largely reduced with the addition of GNS–Co3O4 and GNS–NiO as revealed from the thermogravimetric analysis/infrared spectrometry. The improvement in the fire safety is mainly due to the combination effect of physical barrier of graphene layers and catalytic carbonization of metal compounds. [Copyright &y& Elsevier]

Novel organophosphorus modified nanoparticles (FRs-nanoparticles) were synthesized by the hydrolysis and condensation of both 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide modified vinyl trimethoxy silane (DOPO-VTS) and 3-triethoxysilylpropylamine. FRs-nanoparticles were incorporated into the polyurea matrix in different ratios via in situ polymerization, resulting in the formation of organic/inorganic nanocomposites. The nanocomposites were characterized by thermogravimetric analysis (TGA), real-time fourier transform infrared spectra (RTIR), microscale combustion calorimeter (MCC) and tensile testing machine. The TGA results revealed that FRs-nanoparticles could slightly catalyze the thermal degradation of the nanocomposites in nitrogen atmosphere, but significantly improve the thermal stability of the nanocomposites in air atmosphere. The T 0.5 (50wt.% weight loss) of the nanocomposites was delayed by 32°C in air atmosphere. Moreover, the char yield increased from 2.3wt.% to 8.9 wt.% at 550°C when the loadings of FRs-nanoparticles was 10wt.%, indicating the catalyzing charring effect of FRs-nanoparticles. The MCC results revealed that all the nanocomposites exhibited much lower flammability compared with virgin polyurea. Furthermore, the tensile test indicated that the FRs-nanoparticles could also improve the mechanical properties of polyurea. [ABSTRACT FROM AUTHOR]

Abstract: A phosphorus and nitrogen-containing compound with high phosphorus content, AC2NP2, was firstly synthesized by the Kabachnik–Fields reaction and followed by esterification with acryloyl chloride. The synthesized comonomer was then incorporated into different amounts of polystyrene via radical solution polymerization. The copolymers were well characterized using Fourier transform infrared (FTIR), UV/vis spectrophotometer, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), microscale combustion calorimeter (MCC) and LOI. The results showed that the AC2NP2 was easily incorporated into the backbone of polystyrene, and the copolymers prepared have high transparency. The glass transition temperature (T g ) of the copolymers was decreased with increasing the AC2NP2 content, due to the introduction of much more flexible molecular chain. The TGA results revealed that the introduction of AC2NP2 units slightly decreased the initial decomposition temperatures, but significantly improved the thermal stability of copolymers at high temperature regions under both nitrogen and air atmosphere. Furthermore, all the copolymers exhibited much lower flammability as compared with virgin polystyrene. [Copyright &y& Elsevier]

Abstract: Poly(DOPO substituted dihydroxyl phenyl pentaerythritol diphosphonate) (PFR) was synthesized via the reaction between 10-(2,5-dihydroxyl-phenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-BQ) and pentaerythritol diphosphonate dichloride (SPDPC). The structures of PFR were characterized by Fourier transformed infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1H NMR). Thermal degradation behaviors and flame retardant properties of the epoxy resin (ER)/PFR systems were investigated from the thermogravimetric analysis (TGA), UL-94 test and the limiting oxygen index (LOI) test. Moreover, the surface morphology of the char residue was studied by scanning electron microscopy (SEM). When the PFR content reached 10wt%, the epoxy resin system met the UL-94 V0 classification and the LOI value of 30.2. The microscale combustion calorimetry (MCC) was used to evaluate the combustion behaviors of the ER/PFR. It was found that the addition of PFR obviously decreased the value of peak heat release rate and total heat release of the hybrids. The TGA results showed that the epoxy resin with 10wt% PFR exhibited high char yields. The high char yields and the high limiting oxygen index values were found to certify the excellent flame retardancy of this phosphorus-containing epoxy resin. [ABSTRACT FROM AUTHOR]

Abstract: A novel phosphorus monomer, 2,2-dimethyl-1,3-propanediol acryloyloxyethyl phosphate (DPHA), has been synthesized through phosphorus oxychloride reacting with neopentyl glycol and 2-hydroxyethyl acrylate (HEA). Its structure was characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR) and 31P nuclear magnetic resonance spectroscopy (31P NMR). A series of UV-curable resins were manufactured by blending DPHA with triglycidyl isocyanurate acrylate (TGICA) at different weight ratio. The fire performance was examined by Microscale Combustion Calorimetry (MCC). The results obtained from MCC indicated that the addition of DPHA to TGICA decreased the peak heat release rate (PHRR), heat release capacity (HRC) and total heat of combustion (THC). The char residues of the composites were observed by scanning electron microscopy (SEM). The thermal decomposition behavior of DPHA/TGICA composites was characterized by using thermogravimetric analysis/infrared spectrometry (TGA-IR). The test results indicated that when the weight ratio of DPHA: TGICA=1/1, the onset temperature of the composite was highest and the largest char residue at 700°C was observed. The change of chemical structure during the thermal degradation process was monitored by real-time FTIR analysis. TGA-IR results indicated that the evolved products were CO, CO2, water, NH3, carbonyl, phosphorus oxides and aromatic compounds according to the temperature of onset formation. [Copyright &y& Elsevier]

Co 3 O 4 /COFs nanohybrids are prepared through ball milling of covalent organic frameworks (COFs) nanosheets synthesized from condensation reaction between melamine and o -Phthalaldehyde and then modified with Co 3 O 4 particles first. Polypropylene (PP) composite with different weight loading of Co 3 O 4 /COFs nanohybrids has also been prepared. Successful preparation of Co 3 O 4 /COFs nanohybrids has been proved by the typical reflections of Co 3 O 4 including (111), (220) and (222) in XRD pattern, O–Co–O (663 cm −1 ) and Co–O (569 cm −1 ) stretching vibrations in FTIR spectrum and Co 3 O 4 particles with a diameter from 20 to 50 nm on COFs nanosheets in TEM image. Flame retardant, smoke and carbon monoxide (CO) suppression and thermal properties of PP have been enhanced obviously. The temperature at initial degradation and the maximum weight loss rate of PP loaded with 3.2 wt% Co 3 O 4 /COFs nanohybrids increase 21 °C and 49 °C under air compared with that of untreated PP, respectively. The total smoke release (TSR) of PP loaded with 0.2 wt% Co 3 O 4 /COFs nanohybrids decreases by 22% compared with that of PP 0. The pyrolysis products of PP composite including hydrocarbons, carbon dioxide and CO also decrease. The feasible mechanism for inhibiting fire hazard of PP composite has also been proved. This work broadens application of COFs derivative into polymer matrix. [ABSTRACT FROM AUTHOR]

The objective of this study is to explore the potential of layered zinc hydroxide nitrate modified with sodium benzoate as nanoparticle in thermoplastic polyester elastomer (TPEE). The organically modified zinc hydroxide nitrate was compounded with TPEE using solution blending method. The nanocomposite structure was characterized by means of X-ray diffraction and transmission electron microscopy. The results showed that the nanoparticle was homogenously dispersed in TPEE matrix, and partially exfoliated structure was formed. The thermal behavior, mechanical and thermal combustion properties of the novel nanocomposite were studied respectively through differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA) and microscale combustion calorimeter (MCC). For the nanocomposite containing 7 wt% nanoparticle, the crystallization temperature evaluated by DSC was increased by 10 °C. The storage modulus at −95 °C measured by DMA was improved by around 26%. The heat release capacity (an indicator of a material fire hazard) from MCC testing was reduced by about 56% (compared to the results of neat TPEE). [ABSTRACT FROM AUTHOR]

Abstract: Mixing of aqueous suspensions of indium chloride, tin chloride and graphene oxide leads to the instantaneous precipitation of a hybrid material followed by the calcination under inert atmosphere at 450 °C results in Sn–In mixed oxide nanoparticles deposited on graphene sheets. This hybrid material is characterized by X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy and transmission electron microscopy. The Sn–In mixed oxide nanoparticles with the diameter of ∼10 nm are uniformly attached onto the surface of graphene. The Sn–In mixed oxide/graphene (Sn–In/G) hybrids exhibit superior Li-storage properties over graphene and bare Sn–In mixed oxide, and the optimum molar ratio of Sn–In mixed oxide/graphene is 1:1. With the Sn–In mixed oxide/graphene mass ratio of 1:1, the hybrid exhibits high cyclic stability and capacity retention, where 708 mA h g−1 and 570 mA h g−1 could still be obtained after 10 and 30 cycles, indicating potential application in electrode materials for lithium ion batteries. [Copyright &y& Elsevier]

Abstract: This paper reported the UV-curing flame retardant film, which consisted of epoxy acrylate resin (EA) used as an oligomer, tri(acryloyloxyethyl) phosphate (TAEP) and triglycidyl isocyanurate acrylate (TGICA) used as flame retardant (FR). The flame retardancy and thermal properties of films were reinforced by using alpha-zirconium phosphate (α-Zr (HPO4)2H2O, α-ZrP). The morphology of nanocomposite film was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the organophilic α-ZrP (OZrP) layers were dispersed well in epoxy acrylate resin. Microscale Combustion Calorimeter (MCC), thermogravimetric analysis (TGA) and thermogravimetric analysis/infrared spectrometry (TGA-IR) were used to characterize the flame retardant property and thermal stability. It was found that the incorporation of TAEP and TGICA can reduce the flammability of EA. Moreover, further reductions were observed due to the addition of OZrP. The char residue for systems with or without OZrP was also explored by scanning electron microscopy (SEM). [Copyright &y& Elsevier]

A coating comprising graphene oxide (GO) and oleic acid (OA)-modified zeolitic imidazolate frameworks-8 (ZIF-8) was deposited to cotton fabrics with the aim of obtaining a flame-retardant, self-cleaning and superhydrophobic features. SEM images showed a rough surface with hierarchical structure for GO-cotton/ZIF-8. Existence of the coating on the surface of cotton fabrics was proved by XPS spectra and FT-IR characterization. Surface of the GO-cotton/ZIF-8 fabrics achieved a remarkable degree of thermal and mechanical stability and superhydrophobicity. The results from a flame test demonstrated a protective effect of the coating on the cotton fabrics against fire. Additionally, the GO-cotton/ZIF-8 cotton showed superior self-cleaning ability and oil/water separation performance due to its superhydrophobic surface. Thus, it has a wide range of potential applications in military equipment and outdoor clothing. • Flame-retardant and superhydrophobic coating was deposited on cotton fabric. • The coated cotton fabric exhibited outstanding flame retardancy. • The PHRR and the THR of the coated cotton fabric were reduced by 30% and 53%. • The coated cotton fabric showed oil/water separation efficiency higher than 92%. [ABSTRACT FROM AUTHOR]

Flame retardant rigid polyurethane foam (RPUF) with a reactive melamine-derived polyol (MADP) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were fabricated through free-rise technique. The thermal stability and fire behaviors of RPUF were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), and cone calorimeter. In comparison with the results of RPUF and RPUF/MADP, RPUF/MADP-DOPO displayed higher compressive strength, owing to the two stiff phenyl groups of DOPO. Moreover, with only 7.5 wt % MADP and 7.5 wt % DOPO loading, the MADP/DOPO system endowed RPUF with enhanced char formation, increased LOI value of 28.5% and reduced heat release. Scanning electron microscope (SEM) images, X-ray photoelectron spectroscopy (XPS) analysis and Raman spectra of the char residues suggested that the formation of compact, continuous char layer. The thermal degradation was characterized using thermogravimetric analysis/infrared spectrometry (TG-IR) and chemical structure changes during the thermal degradation were monitored by real time Fourier transform infrared (RT-FTIR), these results demonstrated that the partial phosphorus from DOPO remained in the residual char, but the introduction of MADP significantly promoted generating more stable aromatic structure and enhanced the strength of the char layer formed. Furthermore, MADP facilitated the formation of more H 2 O and CO 2 and diluted the flammable gases in gaseous phase. Based on the analysis, the introduction of MADP/DOPO can endowed excellent flame retardancy to RPUF depending on bi-phase flame-retardant mechanism. [ABSTRACT FROM AUTHOR]

Nano-architecture on the flexible polyurethane foam (FPUF) was built by layer by layer (LbL) self-assembling of α-zirconium phosphate (α-ZrP) and two biopolymers. Through electrostatic attraction and hydrogen bonding between α-ZrP, chitosan and alginate, the nano-coatings were successfully deposited on the substrate. The LbL self-assembly coatings were characterized by X-ray diffraction, UV–vis absorption spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy. This loaded nano-coating endowed FPUF with excellent flame retardancy. Compared with pure FPUF, the reduction in the peak heat release rate of the modified foam with 12.3 wt% weight gain was achieved 71%, and the melt-dripping during combustion disappeared. Meanwhile, the thermal degradation of coated FPUF under nitrogen atmosphere was obviously retarded compared with pure FPUF. Additionally, the mechanical properties of the treated FPUFs were investigated. After loaded with 12.3 wt% nano-coating, the tensile and tear strength were enhanced by 13% and 54%, respectively. These investigations indicated that the study has great potential to add new dimensions in the fire retardancy modification of FPUF. [ABSTRACT FROM AUTHOR]

Nitrogen-doped graphene–ZnS quantum dots (NG–ZnS QDs) were synthesized by a one-pot hydrothermal process using graphene oxide and [(Zn 2 S 2 ) (pa)] nanosheets as precursors. The results demonstrated that ZnS QDs deposited on the surface of the nitrogen-doped graphene (NG). Combined with series of our analysis and characterization, we found that [(Zn 2 S 2 ) (pa)] nanosheets were used not only as the sources of ZnS QDs but also as the sources of nitrogen. Moreover, photocatalytic experiment of NG–ZnS QDs for organic dyes was conducted under visible light irradiation, and the results exhibited that the photocatalytic activities of resultant composites could be remarkably enhanced. This simple and catalyst-free approach for depositing ZnS QDs onto NG may provide an alternative way for preparation of other composites based on NG under mild conditions, which showed their potential applications in wastewater treatment. [ABSTRACT FROM AUTHOR]